Conventionally, as a tank storing a cryogenic liquid such as liquefied natural gas (LNG), a double shell tank made up of an outer tank and an inner tank is known. In this double shell tank, a space between the outer tank and the inner tank is filled with granular perlite as a cold insulation material, and thus a cold insulation layer is formed (see Patent Document 1 below). Further, a resilient blanket (hereinafter abbreviated to “blanket”) for preventing the inner tank from being deformed by a pressure difference between an exterior (cold insulation layer) and an interior of the inner tank is installed on a shell plate (outer wall) of the inner tank.